This invention generally relates to a surgical instrument assembly for use in cutting and retrieving objects from internal body cavities and, more specifically, to a surgical instrument assembly for use in snare cauterization procedures. The present invention also relates to a method for cutting and retrieving objects from internal body cavities and, in a preferred form, to a method for cutting, capturing and/or retrieving polyps and other aggregates of organic tissue from a patient""s internal organs via a snare cauterization procedure.
A wire snare has been used in many different configurations and for many different medical uses. The snare, when equipped for use with cautery, has been used for polypectomies. For example, during a colonoscopy, or other endoscopic procedures, a wire loop or snare, combined with cautery, is frequently used to biopsy or excise lesions. While a wire loop or snare is very effective at cutting free a lesion, it has substantially no ability to capture and/or retrieve the excised legion.
Typically, a second instrument is used to retrieve the excised lesion. The second instrument most often is provided in the form of a wire basket having several loops perpendicular to each other and designed to trap the excised lesion, such as a stone basket used in urology and gastroenterology. The use of two different instruments, one instrument to cut and a second instrument to retrieve, however, is inconvenient, inefficient, time consuming and can sometimes lead to the loss of the excised lesion.
What is still desired is a single instrument that can snare and retrieve a lesion. Preferably, the instrument will be simple in design and reliable in use, and will allow repeated use of a snare or a retrieval configuration, as required, by simple mechanical means.
The present invention provides a simple, but elegant solution to this problem by providing a device for selectively capturing, cutting and retrieving tissue, wherein the device includes a cutting snare, or cauterization wires, that can be incorporated into a retrieval basket configuration also including a basket snare, or basket wires, without removing the cutting snare from a patient""s body. It also allows repeated use of the basket or the snare configuration, as required, by simple mechanical means.
According to one aspect of the present invention, the device includes a handle having an elongated, flexible tube extending therefrom along a central axis to a distal end, a first set of elongated, flexible wires slidingly positioned within the tube and extending along the central axis from the handle to distal ends for extending out of the distal end of the tube, a control tip secured to the distal ends of the first set of wires, the control tip having a slot, and a second set of elongated, flexible wires slidingly positioned within the tube and extending along the central axis from the handle, through the slot in the control tip, to distal ends, the second set of wires coupled at the distal ends. A retaining pin is secured to the control tip and extends through the slot of the control tip and between at least two of the second set of wires. The retaining pin allows the distal ends of the second set of wires to be extended through the control tip, and prevents the coupled distal ends of the second set of wires from being withdrawn from the slot of the control tip and into the tube. In addition, the retaining pin extends the distal ends of the second set of wires from the distal end of the tube upon the distal ends of the first set of wires being extended from the distal end of the tube.
According to one aspect of the present invention, the first set of wires includes two wires. According to another aspect, the second set of wires includes two wires.
According to an additional aspect of the present invention, the control tip is secured to the first set of wires and the slot of the control tip is oriented such that a first reference plane formed by at least two of the wires of the first set and a second reference plane formed by at least two of the wires of the second set are angularly offset. According to a further aspect, the first reference plane is substantially perpendicular to the second reference plane.
According to still another aspect of the present invention, the wires have shape memory such that each of the first and the second sets of wires expand upon being extended from the distal end of the tube. According to an additional aspect, each of the first and the second sets of wires expand to an oval loop upon being extended from the distal end of the tube.
According to a further aspect of the present invention, the device includes a first deployment assembly operatively connected to the first set of wires and allowing a user to selectively extend and withdraw the distal ends of the first set of wires from the distal end of the tube, and a second deployment assembly operatively connected to the second set of wires and allowing a user to selectively extend and withdraw the distal ends of the second set of wires from the distal end of the tube. According to another aspect, a latching mechanism is provided for connecting the first and second deployment assemblies. In accordance with an additional aspect, a locking mechanism is provided for preventing movement of the first deployment assembly.
The present invention also provides a method for selectively capturing, cutting and retrieving tissue in a body cavity using a device as defined above. The method includes inserting into the body cavity the distal end of the elongated, flexible tube, and manipulating the second set of wires from the handle so that distal ends of the second set extend from the distal end of the tube and capture tissue to be cut between at least two wires of the second set. A cauterizing current is then applied to the second set of wires such that the tissue is cut, and the first set of wires is manipulated from the handle so that the distal ends of the first set of wires and the control tip extend from the distal end of the tube and capture the cut tissue between the first and the second sets of wires. The distal end of the tube, together with the first and the second sets of wires and the cut and captured tissue, is subsequently withdrawn from the body cavity.